CN-122028560-A - Flip-chip light emitting diode

CN122028560ACN 122028560 ACN122028560 ACN 122028560ACN-122028560-A

Abstract

The invention provides a flip-chip light-emitting diode, which comprises a substrate, a light-emitting structure, a P-type electrode structure and an N-type electrode structure. The light-emitting structure is positioned on the substrate and comprises a gallium phosphide layer and a semiconductor epitaxial structure, and the gallium phosphide layer is positioned between the substrate and the semiconductor epitaxial structure. The semiconductor epitaxial structure comprises a P-type current dispersion layer, a light-emitting layer, an N-type semiconductor layer and a transparent ohmic contact layer which are sequentially formed. The P-type electrode structure is positioned on the gallium phosphide layer of the light-emitting structure, and the N-type electrode structure is positioned on the transparent ohmic contact layer. The N-type semiconductor layer comprises a distributed Bragg reflector, and the distributed Bragg reflector is positioned between the light-emitting layer and the N-type electrode structure.

Inventors

LIN KUNLI
XIAO YUTONG
CHEN HUANGMING

Assignees

台亚半导体股份有限公司

Dates

Publication Date: 20260512
Application Date: 20250123
Priority Date: 20241112

Claims (10)

1. A flip chip light emitting diode comprising: A substrate; The light-emitting structure is positioned on the substrate and comprises a gallium phosphide layer and a semiconductor epitaxial structure, the gallium phosphide layer is positioned between the substrate and the semiconductor epitaxial structure, the semiconductor epitaxial structure comprises a P-type current dispersion layer, a light-emitting layer, an N-type semiconductor layer and a transparent ohmic contact layer, the P-type current dispersion layer is positioned on the gallium phosphide layer, the light-emitting layer is positioned on the P-type current dispersion layer, the N-type semiconductor layer is positioned on the light-emitting layer, and the transparent ohmic contact layer is positioned on the N-type semiconductor layer; a P-type electrode structure on the gallium phosphide layer of the light-emitting structure, and An N-type electrode structure on the transparent ohmic contact layer; the N-type semiconductor layer comprises a distributed Bragg reflector, and the distributed Bragg reflector is positioned between the light-emitting layer and the N-type electrode structure.
2. The flip chip LED of claim 1 wherein the N-type electrode structure comprises a current confinement layer and a metal reflective layer, wherein the current confinement layer is disposed on the transparent ohmic contact layer and has a plurality of openings, and the metal reflective layer covers the current confinement layer to form an omnidirectional reflector in cooperation with the current confinement layer, and wherein the metal reflective layer forms a plurality of dot ohmic contact structures with the transparent ohmic contact layer through the plurality of openings.
3. The flip chip led of claim 2, wherein the current confinement layer is made of a non-conductive material.
4. The flip chip LED of claim 1, wherein the P-type current spreading layer has a smaller resistance than the N-type semiconductor layer.
5. The flip-chip LED of claim 1, wherein the P-type current spreading layer is an AlGaAs layer with a doping concentration exceeding 1E+19atoms/cm 3 .
6. The flip chip LED of claim 1, wherein the transparent ohmic contact layer is made of a material that does not absorb light of a corresponding light emission band emitted by the light emitting layer.
7. The flip chip led of claim 1, wherein the P-type electrode structure comprises a finger electrode portion and a pad portion, the finger electrode portion contacts the gallium phosphide layer and the pad portion of the light-emitting structure, respectively, and the finger electrode portion is disposed at the periphery of the semiconductor epitaxial structure and is structurally symmetrical based on the center of the semiconductor epitaxial structure.
8. The flip chip LED of claim 7, wherein the finger electrode portion is a frame electrode and the N-type electrode structure is a plurality of dot electrodes or another frame electrode arranged regularly.
9. The flip chip LED of claim 7, wherein the finger electrode portion is a set of parallel line electrodes, and the N-type electrode structure is a plurality of dot electrodes arranged regularly or another set of parallel line electrodes parallel to the finger electrode portion.
10. The flip chip LED of claim 1, wherein the N-type electrode structure is a plurality of dot structures disposed on the transparent ohmic contact layer, and each dot structure forms an ohmic contact with the transparent ohmic contact layer.

Description

Flip-chip light emitting diode Technical Field The present invention relates to a light emitting diode, and more particularly, to a flip-chip light emitting diode capable of reducing the occurrence of electrode shadows. Background In the structural design of the conventional light emitting diode, the electrode is arranged above the light emitting area, so that a shadow area is formed at the position of the electrode under near field optics, and the light emitting effect of the light emitting diode is further affected. The conventional flip-chip led adopts a different structural design from that of the conventional led, and the electrode is disposed below the light-emitting area instead of above the light-emitting area, so as to avoid the conventional led from forming the dark shadow area. However, the electrode and the structure other than the electrode of the conventional flip-chip led may have different reflectivity due to different materials, so that the electrode may form another shadow region under the near-field optics even if it is disposed under the light-emitting region, which may affect the light-emitting effect of the flip-chip led. In addition, if the current distribution of the flip-chip light emitting diode is uneven, the shadow area formed by the electrode is more obvious. Therefore, how to design a flip-chip light emitting diode capable of improving the above problems is a considerable research problem. Disclosure of Invention The invention aims to provide a flip-chip light-emitting diode capable of reducing the occurrence of electrode shadows. In order to achieve the above objective, the flip-chip light emitting diode of the present invention includes a substrate, a light emitting structure, a P-type electrode structure and an N-type electrode structure. The light-emitting structure is positioned on the substrate and comprises a gallium phosphide layer and a semiconductor epitaxial structure, and the gallium phosphide layer is positioned between the substrate and the semiconductor epitaxial structure. The semiconductor epitaxial structure comprises a P-type current dispersion layer, a light-emitting layer, an N-type semiconductor layer and a transparent ohmic contact layer. The P-type current spreading layer is positioned on the gallium phosphide layer, the light-emitting layer is positioned on the P-type current spreading layer, the N-type semiconductor layer is positioned on the light-emitting layer, and the transparent ohmic contact layer is positioned on the N-type semiconductor layer. The P-type electrode structure is positioned on the gallium phosphide layer of the light-emitting structure, and the N-type electrode structure is positioned on the transparent ohmic contact layer. The N-type semiconductor layer comprises a distributed Bragg reflector, and the distributed Bragg reflector is positioned between the light-emitting layer and the N-type electrode structure. In one embodiment of the invention, the N-type electrode comprises a current limiting layer and a metal reflecting layer, wherein the current limiting layer is positioned on the transparent ohmic contact layer and is provided with a plurality of openings, the metal reflecting layer covers the current limiting layer to form an omnidirectional reflecting mirror in cooperation with the current limiting layer, and the metal reflecting layer forms a plurality of point-shaped ohmic contacts with the transparent ohmic contact layer through the plurality of openings. In one embodiment of the present invention, the current confinement layer is made of a non-conductive material. In an embodiment of the present invention, the resistance of the P-type current spreading layer is smaller than the resistance of the N-type semiconductor layer. In one embodiment of the present invention, the P-type current spreading layer is an AlGaAs layer with a doping concentration exceeding 1E+19atoms/cm 3. In an embodiment of the invention, the transparent ohmic contact layer is made of a material that does not absorb the light emitted by the light emitting layer corresponding to the light emitting band. In an embodiment of the invention, the P-type electrode structure includes a finger electrode portion and a pad portion, the finger electrode portion contacts the gallium phosphide layer and the pad portion of the light-emitting structure, respectively, and the finger electrode portion is disposed at the periphery of the semiconductor epitaxial structure and is structurally symmetrical based on the center of the semiconductor epitaxial structure. In an embodiment of the invention, the P-type electrode structure is disposed at the periphery of the semiconductor epitaxial structure, and the P-type electrode structure is structurally symmetrical based on the center of the semiconductor epitaxial structure. In an embodiment of the invention, the finger electrode portion is a frame electrode, and the N-type electrode structure is a plurality of dot electrod